CHAPTER XIII 



GROWTH AND OLD AGE 



The rate of growth does not increase from birth to 

 maturity and then decline, but declines steadily from 

 the impregnation of the ovum until death. The fetus 

 grows most rapidly during the first month of uterine 

 life the rate of growth declining from this time until 

 the end the average child nearly triples its weight at 

 birth in its first year, but only gains about twenty-five 

 per cent during the second year, and at a still lower 

 rate for each succeeding year. Other changes indicate 

 the gradual loss of the power of living always bones 

 become more brittle, cartilage more rigid, muscles less 

 elastic, all changes which, while serving a useful pur- 

 pose in some cases, none the less show that animals be- 

 gin to die before they are born, and that, independent 

 of disease, death is as natural a process as birth. As 

 few, however, die a natural death, a death which is 

 simply the wearing out of the protoplasm of which the 

 body is made, we have little or no idea of the number 

 of years which a perfectly healthy person might live if 

 no disease or accident intervened to bring life to a sud- 

 den termination. The only authentic case of great lon- 

 gevity is that of Thomas Parr (usually known as "old 

 Parr") who reached the age of one hundred and fifty-two 

 years, and is supposed to have been brought to an un- 

 timely end by high living and drinking. 



The rate of growth, up to the time of puberty (the 

 development of the sexual functions) is greater in girls 



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